you could try to be a smooth operator and send her IOI as well, like make eye contact for one second longer, kick her under the table, say sorry then kick her again, rub her upper arm in a friendly manner when you go, you know, things that are congruent with your serious interest in her, not too playful and flirty like you're an amateur PUA just looking for punani, know what I mean? Make her dream about you day and night.

And the escalation should come from her imho, i mean she should be the one to ask you on a date or come closer to you. This is to protect your professionalism.