(1) As she was driving to visit her twin, Jayla had a strange feeling that something bad was going to happen. (2) Meanwhile, Kayla had the same exact premonition.

(3) Worried about her sister, Kayla called Jayla's cell phone.

(4) Because she took her eyes off the road to answer the phone call, Jayla lost control of her car and crashed through the front of Kayla's house.

What is the function of the introductory word in sentence 2?