Effie
Effie would cast Invisibility, hide in a corner, and just watch and wait to see what happens next.
[if there was time for all that of course, otherwise just roll off the bed and hide under the bed]
DM
[Love the order, just eyes open, invisibility. I will challenge one thing, invisibility has all components so you'll have to say the magic words alerting whoever it is - does that change your decision?]
Effie
[Hmmm, she'd probably risk it. It gives her a chance to control the situation. If it's an attacker they have disadvantage on finding and attacking her (?) or they would have to spend an action to dispel the magic. The probability of it being someone that has active See Invisibility or blindsight/devil sight isn't that high... Right? ]
DM
[Just for fun give me a d100 and a stealth check with advantage whenever you want xD]
[Also love the Effie sleeps with her components handy - super in character imo]
Effie
[Her rapier is her spell focus, of course she has it right there under the pillow ]
[Rolled on DndBeyond: d100 => 38, Stealth => Nat20 + 13 = 33]
DM
[The unseen assailants entered and found nothing but an untidy bed. Cursing they quickly looked around and then spoke to each other planning their next move - while also spilling everything to the hidden Effie. Beyond lying on an uncomfortable wooden floor no harm had befallen her... And now she knew who she had to pay a visit to.]