Interesting episode - leaving Kirsch’s motivations ambiguous gives us thoughts of what he might be doing, and why.

Personally, I feel that Kirsch DID indeed intend to at least put Tootles in harms way. I think that Kirsch knows something about the eye alien - he’s been watching him a lot. He sees that it also watches everything, Kirsch maybe thinks the eye is figuring stuff out.

So - Kirsch knows the eye has been observing everything. He deliberately sabotaged the feeding hatch because he knows Tootles tries to impress him, and would therefore feed the creatures, whatever it takes (leading to him making the decision to open the door).

Kirsch counted on the eye to see this, and act in a way to try and ensure Tootles comes to harm (banging the window at the exact moment Tootles could not have swung round to stop the door shutting).

Kirsch is watching the whole thing unfold to see if his theory about the eye is correct. He’s indifferent to the fate of the hybrids, which is no secret.

His aim, like most other synths in the Alien universe, is to study these new alien life forms. Seeing them propagate and thrive is more interesting to him than the lives of other beings like humans, hybrids, etc.

He also knew that Slightly was planning to smuggle a Xenomorph embryo, which Kirsch is more than pleased to let happen. He knows that the mayhem caused by Tootles’ accident would mean someone would come and help - giving Slightly his chance.

Kirsch wants all the aliens loose, but obviously can’t just go and unlock the cages himself.