By the time you have realised that the key is inside, it is already too late. The desperate lunge to stop the door shutting is futile. You clench your fingers around your thumbs and squeeze hard, then exhale in an attempt to subdue the rising frustration in your stomach. You have locked yourself out of your flat.
With an expired card from a rarely visited pocket of your wallet, you try to tickle the lock open. Fifteen minutes later, a mangled piece of plastic and a firmly shut door confirm that you were right to choose a lifestyle inside the law.
The locksmith arrives after an hour. He slides a sheet of plastic between the door and the frame, and with a firm downward swipe, it acquiescently clicks open. Was the solution that simple all along?
Real Madrid have lost two consecutive matches this week: the first at the hands of Pablo Machin's Girona, and the second under the Wembley arch against Tottenham Hotspur. Both defeats were inflicted by teams operating a system with three centre-halves and marauding wing-backs on each flank.
The above yarn about involuntary, short-term self-destitution is a euphemism for Real Madrid's alarming vulnerability to that particular tactical system. Los Blancos appeared impenetrable last season. It seemed impossible to open the door. Yet Machin and Mauricio Pochettino, in their role as the locksmith, have slid their tactical templates over the lock and watched the door swing open.
Real Madrid are inherently susceptible against teams that set up with three defenders and mobile wing-backs. There are two clear reasons for this. Firstly, such systems expose Madrid's emphasis on attacking through the full-backs. Secondly, the trio of centre-halves isolate Cristiano Ronaldo and Karim Benzema from each other.
Real Madrid look to their full-backs to provide width and an attacking outlet. Across all competitions in the 2016-17 season, Marcelo provided 14 assists and Dani Carvajal 15 as Madrid cut through opposition with a serrated edge.
They have become increasingly important to the Real Madrid attack since the form of Isco and injury to Gareth Bale prompted Zinedine Zidane to replace a 4-3-3 formation with a fluid 4-3-2-1. In the previous formation, the wingers stretched play across the pitch. Now, that task falls upon the full-backs.
The heat maps that charted the average positions of Marcelo and Achraf against Girona and Tottenham decorated the intersection of the half-way line and the touchline in a shade of red. The full-backs act as auxiliary wide midfielders and usually occupy more advanced positions than Toni Kroos, Casemiro or Luka Modric.
This becomes problematic when Real Madrid face wing-backs who are liberated by the presence of three centre-halves behind them. They can attack the space that Marcelo and Achraf leave behind them.
Pablo Maffeo and Aday Benitez profited for newly promoted Girona. Ben Davies and, in particular, Kieran Trippier took advantage for Tottenham. Of Girona's attacks, 79 percent came down the flanks. The figure was 75 percent for Tottenham.
Pochettino identified the space behind Marcelo as Madrid's soft underbelly. A long, diagonal pass to Trippier followed by a first-time cross was Spurs' weapon of choice. Dele Alli could not convert the first time they tried it. The second time, he scored the opener. Trippier had strayed offside, but it nevertheless exposed Madrid's weakness.
It presents a conundrum for Zidane. The full-backs are integral to attacking combinations in his system, but their importance simultaneously creates a weak point that teams with tactical nous can exploit. The poor form of Marcelo, and Dani Carvajal's absence with a pericardium infection, further compound the issue. Yet it is a systemic flaw that runs deeper than personnel.
The second issue for Real Madrid is that teams with three centre-halves are able to isolate Ronaldo and Benzema from each other. Two of the defenders can man-mark, leaving one spare to act as a sweeper.
Pochettino acknowledged after the final whistle at Wembley that this had formed part of his plan.
"We cut out the connection between Ronaldo and Benzema and we made them leave the area to pick up the ball. It was difficult but I'm happy," the Argentine said.
Zidane attempted to solve the problem against both Girona and Tottenham by mimicking the opposition's system. In each match, Casemiro dropped in to a back-three alongside Nacho and Sergio Ramos. And in each match, the intended solution created distinct problems. With Casemiro absent from the midfield, Real Madrid became porous and susceptible to the counterattack through the middle.
The French coach's reaction to the current malaise will be definitive, both in terms of the short-term tenability of his position at Real Madrid -- a club in which crises are perpetually imminent -- and his general reputation as a manager. Zidane risks being discarded as the mere inheritor of a talented squad; someone who happened to arrive at the right time and made subtle tweaks to deliver success.
The headline of Diario AS on Friday read: "Zidane's Labyrinth," which reflects that there is not a straightforward fix at Real Madrid. The systemic vulnerability to the "three-man defence with wing-backs" approach needs attention. But so too does the lack of squad depth compared to last season, the questionable form of individual players, and a seeping complacency.
Real Madrid host Las Palmas on Sunday evening. The visitors from the Canary Islands have lost their last six matches in La Liga, scoring three goals and conceding 18 in the process. They will also be without talismanic playmaker Jonathan Viera. In short, Las Palmas appear ideal fodder for Real Madrid as they look to heave their season back on course.
That is, of course, unless Las Palmas get their wing-backs out.
