Why is a player's agent a 'poison pill'? What does that mean?

Palace since 19 August 1972. Palace 1 (Tony Taylor) Liverpool 1 (Emlyn Hughes)

I don’t know what Bayern are moaning about, even at £55m it’s an absolute steal.

I think the only reason other teams haven't snapped up Williams is that he is looking for 350,000 a week

If there is any confusion you would imagine it's not what they need to pay Palace, but rather what they have to pay Reading and Olise. Possibly the figure is £43 million to Palace, but then say £5 million to Reading and £2 million to Olise's team. It's possibly Palace have said that they won't negotiate on their end, but feel free to speak to Olise.

Pure speculation on my part, but that way it's on Olise and if he's that keen to move he drops his cut of the deal, or takes a lower wage.

I know that this has been discussed ad infinitum on here but if he had a release clause figure then, when triggered, that is it.
IF BM are the team he wants to join then all they have to do is settle with us and any other parties involved that need paying - unless we pay them - and the deal is done.
Why is there a discrepancy?
I think that the deal will be called off and that he will be with us next season, the way it appears to be going.

I suspect the release clause has been triggered, however, the payment terms may be the sticking point. Foreign clubs can negotiate longer term payment terms over the length of the contract, whereas British clubs have to pay in full within 12 months.
BM want the former we want the latter, hence the delay in the medical being completed