I think there might have been some strategy behind this (I’m not saying it was the best one, or that everything went perfectly).
Let’s look at it this way: we have 3 containers, and it’s not in the Mole’s interest for their container to open first. If it opens first – sure, they can get there quickly. They could also argue to leave the suitcase behind and take the rewards for themselves, BUT there’s a risk – what if the other two want to get rid of it? Mole can be outvoted.
Generally, the Mole would prefer that NO ONE DO IT ON TIME – then there are no dilemmas, the suitcase stays, and there's no need to rely on people and their decisions.
So ideally, they’d want to be the second group to leave – BUT NOT TOO SOON. That’s why it would be beneficial for the Mole to control the situation and delay solving the task long enough for someone else to go first.
I still believe that the task with the nose and the swearing is easier to manipulate – if it’s going too well, the Mole can just swear a couple of times; if it’s going too slowly, they can rub their nose a few times.
Alright, now the Mole hears that the first container has been opened. But their goal is still tO SLOW THE GAME, so leaving right away – like a minute later – is risky. Why?
1. First of all, if the first group gives a wrong answer, they’ll have to wait for the second group to overtake them. And if that group is right behind – there’s still plenty of time. It’d be better if that gap was slightly bigger, like 10 minutes, for example. So the Mole waits a little bit longer...
2. Secondly – leaving one or two minutes later could also raise suspicion, especially in the “nose rubbing” container – they don’t want the others to get suspicious, and it needs to look natural. Seriously, imagine you’ve been working on a riddle for 30 minutes, and suddenly the other group opens their container – and someone in your group “SUDDENLY" figures out it’s about touching your nose - within a minute – SUPER SUSPICIOUS. The Mole can’t afford that. So they have to slow it down a bit.
I still have my eye on Michelle (and Alexy) – and I think this kind of reasoning doesn’t rule them out at all. In fact, it makes me totally understand why they were the last to leave. Unlucky that Hilde and Nimrod’s container opened faster – it beat the Mole’s plan and their intent to play things a little more cautiously.