WHY must they survive a nightmare abortion clinic?

'Attacked by a mutant newborn calf, a reckless teen couple taking refuge in a nightmare abortion clinic must destroy its cursed guardian or remain trapped forever.'

I know being attacked by a mutant newborn calf might not sound that threatening, but the 'mutant' part should indicate this is not your run of the mill easily dealt with petting zoo style farm animal... and hopefully this should come across.

I mean, I could have gone with 'after nearly being killed on their way to hospital', but although this is the switch between 'ordinary' and 'special world', the mutant calf thing is the bigger indicator of 'we're through the looking glass, people'...

Yeah, I'm rambling...

Hello, I love the situation (teen couple in abortion clinic), but you must work a plot: what happens ? A monster (NEVER use names that means nothing in a logline) hunts them in the clinic ? What exacly is he inciting event ?