Some attempts later... success!
The first key can be grabbed for free at the start just by being quick, but others require a lot more effort to be grabbed this way. This is not an easy task.
EDIT: And just a little later, billy bob has informed me that there is a very easy way to get the keys 100% consistently... step on the tile next to the key, make one move back, return to that tile again, grab the key and leave. If done with no hesitation, this always works. No timing shenanigans needed. Still proud of doing it the hard way, but if you wanna try this out for yourself, bily bob's setup is much easier.
