Taking a Trade at opening

The reason why alerts are generated and delivered in 10-15 sec is that it takes time to consolidate all the ticks to make sure triggers get generated on the most accurate candles possible. You might have observed that at certain times, the OHLC values of a candle changes after it closes in chart, the reason is the same. The gap is to allow the consolidation so that triggers, would match the chart. Read this post to learn more about this.

But yes, the effort will able be to reduce this gap to enable faster notification,

As regards to triggers based on LTP, while there are many types of strategies that use LTP or perhaps TBT data for placing trades, they are currently not possible to be implemented, unfortunately.