Radiant stops sending stormlight to the map and summons Pattern as a shardblade

In addition to the young noblewoman's illusions? Leareth magical sensors notice

All of the the elementalish things in (except the one connected to the man in black) in the room become glowing magical weapons in the hands of the people they're connected to

additionally a large number of smaller elemental things briefly appeared in the room before fusing into to a full set of glowing plate covering the woman with the crown

And everyone with a connection including the person hiding in the air vent is drawing in magical power from their pouches visible to the naked eye as glowing white smoke

Navani runs for the door to warn the the rest of the tower of Intruders.

A few short years ago she would have got  the guard but if 4 Knights radiant one of whom is in plait can't stop this stranger there's nothing to ordinary soldiers can do

Wit stays perfectly still and everyone stops noticing him

Everyone else in the room starts approaching Leareth weapons drawn

Leareth quickly mind speaks to everyone except the person in the air vent <my apologies I was experimenting with a new form of gate spell and arrived here by accident my name is Leareth I don't mean you any harm>

He also puts his hand up in what base his experience he's pretty sure is a universal gesture

frowns and waves to his fellow knights hold there position 

Then with his sword drawn but not pointing at Leareth he stepps behind him and places a hand on his shoulder 

Magic runs down his arm and into Leareth's shoulder forging a connection between them

Dalinar let's go and says in a language Leareth hasn't heard for hundreds of lifetimes "hello Leareth where are you from? and are you trying to build an oath gate?"

Between being at the top of a incredibly magically powerful tower and hearing the language of his long dead home Leareth is having a remarkable hard time thinking what to do